Eagle Springs Oil Field East Extension – a 1965 Soil Gas Survey Success

Louis C. Bortz, Independent, 1775 Sherman Street, Suite 1900, Denver, CO 80203, phone: 303 831-1912, [email protected]

Eagle Springs, Nevada's first oil field, discovered in 1954 by Shell Oil Company, has produced 5,103,703 BO through October 2004. The discovery well was completed pumping 343 BOPD, and Shell drilled three additional oil wells and three dry holes by 1961 and then farmed out the non-producing portion of the field to Texota Oil Company in July 1963. Texota completed 2 successful extension wells, and afterwards a Horvitz-type soil gas survey was completed in August of 1964 which resulted in a distinct “Ethane Plus” anomaly 1/2 mile east of the Texota wells. Subsequently, 6 more successful extension wells were drilled by Texota and Western Oil Lands within the anomaly.

The soil gas anomaly can be directly related to the boundary fault zone being a leaky trap and the faults have provided a direct migration path from the reservoir to the surface. Soil gas anomalies have been mapped over other Nevada oil fields (Trap Springs, Blackburn and Grant Canyon), however, these anomalies were either not recognized prior to drilling the discovery or the soil gas surveys were done after the discovery. Also, in Nevada, many dry holes have been drilled on “strong” soil gas anomalies. The message remains: soil gas surveys must be combined with geology and geophysics to identify drillable prospects.